The correct option is D nπ±π3, n∈Z
Given: sin2x+sin4x+sin6x=0
⇒(sin6x+sin2x)+sin4x=0⇒2sin4xcos2x+sin4x=0⇒sin4x(2cos2x+1)=0⇒sin4x=0 or 2cos2x+1=0⇒sin4x=0 or cos2x=−12⇒sin4x=0 or cos2x=cos2π3⇒4x=nπ or 2x=(2nπ±2π3), n∈Z
Hence, the general solution is
x=nπ4 or x=(nπ±π3), n∈Z